prescriptivist

Definitions

from Wiktionary, Creative Commons Attribution/Share-Alike License

n. Someone who lays down rules regarding language usage, or who believes that traditional norms of language usage should be upheld.

adj. Having a tendency to prescribe.

from the GNU version of the Collaborative International Dictionary of English

n. A person who believes that acceptable practices should be prescribed by an authority rather than be determined by the usage of the general public; especially, a supporter of prescriptive{2} rules of grammar; -- also used attributively, as prescriptivist grammar.

Etymologies

from Wiktionary, Creative Commons Attribution/Share-Alike License

prescriptive +‎ -ist

Examples

Likewise, to the dismay of us linguists, National Grammar Day will mostly just result in prescriptivist dilettantes coming out in full force, tossing around ignorant grammatical proclamations with gusto, like so many dimes at a dime toss.

This isn’t out of the ordinary for prescriptivists; hardly a month goes by without the Language Loggers pillorying some foolishly certain prescriptivist for breaking the very rule the prescriptivist was trying to impose.

This kind of prescriptivist stance says that science fiction should only be the kind of thing Heinlein meant when he described sf as "realistic speculation about possible future events" (but he had aliens, the mundanistas will say, so what did he know ...).

I would encourage you all to withold judgement based on one quiz and read his essay based on this whole prescriptivist/descriptivist war which lays out his rationale for teaching students some of these rules that people disagree with.

Every time I mention the no-sentence-final-prepositions rule as an example of unfounded prescriptivism, I always get a response from someone along the lines of “Oh, no prescriptivist actually believes that anymore.”

A follower of the linguistic school of thought that says there is one true way to use language (usually the rules we are indoctrinated with in school) and that deviances from it in real life are wrong and should be frowned upon.